Niner

JET 9 RDO Mountain Bike Frameset

Ever since the RKT stepped in to take the role of the XC full-squish whippet in the Niner lineup, the JET 9 RDO Mountain Bike Frameset has been free to, ahem fly, as the brand's quintessential trial machine. Sitting right between the aforementioned Jet and the all-mountain, enduro bruiser, the Rip 9, the Jet has 120mm of plush Continuously Varying Arc (CVA) travel on tap that possesses the ability to tame rough trails at speed with better control and has the ability to be run as a 29er or in 27.5+ guise. And since this frameset is poised to go just as quickly downhill as it does uphill, its geometry is dialed for all-day epics with plenty of ups and downs with a slack headtube, steep seattube, and long reach. This frame is ready for you to build it up with that trusty kit off of your current ride or become the foundation of your dream build from the ground up.

It took a few years for boost spacing to establish itself as the industry standard but thankfully it allows frame builders like Niner to update its geometry to what we spoke to above. Gone are 21mm off of the new frame's chainstays helping to move the rear wheel underneath the rider for better traction and responsiveness. So even though this new Jet is more capable and has more travel than the old one, it hasn't lost its nimbleness. For fork lengths, Niner recommends paring a 130mm for 29-inch wheels and a 140mm variety with 27.5+ and despite the newer, slacker front end, the seat tube angle remains similar to the older Jet 9 despite its shorter travel fork and steeper head tube angle. That steeper seattube is responsible for keeping you on top of the pedals for more efficient pedaling, more intuitive handling, and helps keep the front end from wandering on steep uphill switchbacks.

With the recommended fork lengths for 29 and 27.5+ wheels mentioned above, the respective headtube angles sit at either 67.5 or 67 degrees. While riding, that angle is a pretty good balance between a quick and agile trail machine and a point-and-shoot sled that continues to add confidence as both speed and gradient increase. The modern longer reach paired with a shorter stem lengthens the overall wheelbase so you get tons of stability over fast, wide open stretches of the trail while it doesn't detract from doing the singletrack dance on tight trails.

Some other frame builders offer two-tiers of carbon construction, one that's its halo model, and a more economical version that might add a little weight or lose a bit of stiffness or both. Not with Niner. Every carbon frame it produces gets its Race Day Optimized (RDO) treatment. Its methodical compaction method squeezes out all of the excess resin and compacts the carbon ensuring uniform wall thickness. This gives Niner exact control over the material and lets the engineers reduce weight, add stiffness and durability, and overall tune the bike to how they want it to ride.

On this frame, the FOX Float DPS shock's stroke is governed through the CVA patented platform that Niner originally designed to work specifically with 29-inch wheels. Since 27.5+ wheels are pretty damn close to the same overall diameter, its use for either wheel size works equally well with both. CVA relies on counteracting linkage forces that are not dependent on specific pivot locations. The bottom linkage is pulled downward when you're pedaling to negate squat, while the upward rotating top linkage is left free to react to terrain changes. What you get is an efficient, fun, and fully active suspension system, all the time.

Finishing details check off everything on the list of what we want in a modern mountain bike and we completely endorse its inclusion of a BSA threaded bottom bracket. Pressfit shells might be lighter and easier to manufacture, but the tighter tolerances of a CNC-machined thread cannot be matched by any pressfit interface. The threading ensures the bearing cups install correctly and parallel with one another which reduces wear over time and virtually eliminates creaks, groans, and pops that so often plague pressfit models. The places near the crank and bottom bracket area on the mainframe and chainstays are protected with titanium plates for long-term durability. The frame also features a battery storage compartment if you get the itch to go with Di2 shifting on the build. Tire clearance is rated up to 2.6-inches in the 29er format and 3.0-inches in 27.5+.